The subject matter disclosed herein relates to imaging systems and, in particular, to the independent assessment of an operating voltage within an imaging system.
In the fields of medical imaging and security screening, non-invasive imaging techniques have gained importance due to benefits that include unobtrusiveness, convenience, and speed. In medical and research contexts, non-invasive imaging techniques are used to image organs or tissues beneath the surface of the skin. Similarly, in industrial or quality control (QC) contexts, non-invasive imaging techniques are used to examine parts or items for hidden defects that may not be evident from an external examination. In security screening, non-invasive imaging techniques are typically used to examine the contents of containers (e.g., packages, bags, or luggage) without opening the containers and/or to screen individuals entering or leaving a secure location.
A number of non-invasive imaging modalities exist today. A particular modality may be selected based upon the imaging context, such as the organ or tissue to be imaged, the spatial and/or temporal resolution desired, or upon whether structural or functional characteristics are of interest. Certain of these imaging modalities may operate by generating electromagnetic energy, such as X-rays, that is attenuated upon passing through subject or object being imaged. The differential attenuation of the X-rays or other energy may be used to formulate an image of the internal structures of the subject or object being imaged.
In certain contexts it may be desirable to periodically assess that the dose of X-rays or other energy being generated for imaging purposes corresponds to what has been specified by the operator of the imaging system. For example, regulations may specify that computed tomography (CT) or other X-ray generating imaging systems be periodically evaluated to confirm that the actual dose of X-rays generated by such an imaging system corresponds to the dose that is prescribed or specified. Such an evaluation may involve the measurement of certain operating parameters of the imaging system, such as the operating voltage (measured in kV) in the case of an X-ray based imaging system. Further, such evaluations should be conducted using instrumentation and/or techniques that are independent of the imaging system. That is, it is generally not deemed sufficient to rely solely on the instrumentation provided with the imaging system as such instrumentation may be subject to any defects or problems associated with the imaging system as a whole.
Further, in the case of X-ray based imaging systems, because of the high voltages involved, conventional, off-the-shelf measurement devices may be unsuitable to perform the desired measurement. As a result, techniques are typically employed that are obtrusive (requiring that the imaging system be opened) and time consuming and which utilize highly trained personnel, such as field engineers.